IAEA secret report: Highly enriched uranium found in 'Isfahan tunnels'

Vienna–Tehran–Agencies: Confrontation between Iran and the International Atomic Energy Agency (IAEA) has been renewed over the nuclear inspection file, with growing international concern regarding an underground uranium enrichment facility in Isfahan. Tehran has refused to resume inspections under the “exceptional circumstances” following attacks on its nuclear sites, unless the root causes of the crisis and its security concerns are addressed.

The IAEA, in a confidential report whose contents were relayed by Reuters and Agence France-Presse, expressed increasing concern about the facility Iran announced last year, noting that it has been unable to determine its precise location or assess its status under safeguards, nor verify whether it contains nuclear materials. The agency confirmed it has not received information from Tehran regarding its nuclear facilities and materials, except for the Bushehr nuclear power plant. It emphasized that access for its inspectors to Iranian facilities is essential, calling on Iran to take technical and gradual measures to create conditions for the resumption of inspections.

Iran has not allowed IAEA inspectors to return to any of its nuclear facilities that were bombed by Israel and the United States in a 12-day campaign in June of last year, which destroyed or severely damaged other Iranian uranium enrichment facilities that form the core of its nuclear program. The targets included a tunnel network in Isfahan. Diplomats believe the Isfahan fuel enrichment facility, which Iran announced to the IAEA on June 12, 2025, is located within this network, although a senior diplomat stated that its location and status remain unknown.

The IAEA had intended to inspect the facility on June 13, 2025, but the bombing campaign began on that day, making the inspection impossible. IAEA Director General Rafael Grossi said in March that the agency believes a large quantity of Iran’s highly enriched uranium is located in the Isfahan tunnel complex.

The report focused on the Isfahan fuel enrichment facility but reiterated that Iran must inform the IAEA of the status of its enrichment facilities, as well as its stockpile of highly enriched uranium, which includes material close to weapons-grade enrichment levels, and allow inspectors to return to the bombed sites to account for the enriched uranium.

“The Agency’s lack of information about these nuclear materials and its inability to access facilities to verify them constitutes a serious concern regarding nuclear proliferation... and must be rectified as quickly as possible.”